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Introduction to Database Management

Learn about the qualities of valuable information, functions of DBMS, importance of data to organizations, and characteristics of different types of databases. Explore terms like character, field, record, and file, and understand how web databases work.

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Introduction to Database Management

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  1. Chapter 10 • Database Management TE-102 Introduction to Computing http://web.uettaxila.edu.pk/CMS/UG/TE-102/

  2. Chapter 10 Objectives Next Identify the qualities of valuable information Discuss the functions common to most DBMSs Explain why data is important to an organization Describe characteristics of relational, object-oriented, and multidimensional databases Discuss the terms character, field, record, and file Explain how Web databases work Identify file maintenance techniques Discuss the responsibilities of database analysts and administrators Differentiate between a file processing system approach and the database approach

  3. Data and Information Next • How are data and information related? • Data is raw facts • Information is data that is organizedand meaningful Step 2. The computer extracts the member data from disk. • Computers process data into information receipt processing Step 1. The member data, including a photograph, is entered and stored on the hard disk. data stored on disk Step 3. The receipt is created and printed. p. 10.02 Fig. 10-1

  4. Data and Information Createdatabase Createforms and reports Add, change, and delete data Sort and retrieve data Click to view animation Next • What is a database? Collection of data organized so you can access, retrieve, and use it Database softwareallows you to Database software also called database management system (DBMS) p. 10.03

  5. Data and Information Next • What is data integrity? Garbage in • Degree to which data is correct • Garbage in, garbage out (GIGO)—computer phrase that means you cannot create correct information from incorrect data Garbage out Data integrity is lost p. 10.03

  6. Data and Information Next • What are the qualities of valuable information? Accurate Verifiable Timely Organized Accessible Useful Cost-effective p. 10.04

  7. The Hierarchy of Data Next • What is a hierarchy? • Database contains files, file contains records, record contains fields, field contains characters p. 10.05 Fig. 10-2

  8. The Hierarchy of Data Next • What is a field? • Combination of one or more characters • Smallest unit of data user accesses • Field sizedefines the maximum number of characters a field can contain • Field name uniquely identifies each field • Data type specifies kind of data field contains p. 10.05 Fig. 10-3

  9. The Hierarchy of Data Text (also called alphanumeric)—letters, numbers, or special characters Numeric numbers only AutoNumber unique number automatically assigned to each new record Currency dollar and cent amounts or numbers containing decimal values Date month, day, year, and sometimes time Memo lengthy text entries OLE (also called BLOB for binary large object)—photograph, audio, video, or document created in other application such as word processing or spreadsheet Yes/No (also called Boolean)—only the values Yes or No (or True or False) Hyperlink Web address that links to document or Web page Next • What are common data types? p. 10.06

  10. The Hierarchy of Data Next • What is a record? Group of related fields Key field, or primary key, uniquely identifies each record p. 10.06

  11. The Hierarchy of Data • Member ID • First Name • Last Name • Address • City • State 2295 • Donna • Vandenberg • 1029 Wolf Avenue • Montgomery • AL 2928 • Shannon • Murray • 33099 Clark Street • Montgomery • AL • 3376 • Adrian • Valesquez • 15 Duluth Street • Prattville • AL 3928 • Jonah • Weinberg • P.O. Box 45 • Clanton • AL 4872 • Marcus • Green • 22 Fifth Avenue • Auburn • AL records key field fields Next • What is a data file? • Collection of related records stored on disk p. 10.07

  12. Maintaining Data Adding records Changing records Deleting records Next • What is file maintenance? • Procedures that keep data current p. 10.08

  13. Maintaining Data Next • Why do you add records? • Add new record when you obtain new data p. 10.08 Fig. 10-5

  14. Maintaining Data Next • Why do you change records? • Correct inaccurate data • Update old data p. 10.09 Fig. 10-6

  15. Maintaining Data Next • Why do you delete records? • When record no longer is needed • Some programs remove record immediately, others flag record p. 10.10 Fig. 10-7

  16. Maintaining Data • SAMPLE VALID AND INVALID DATA • Validity Check • Field Being Checked • Valid Data • Invalid Data Alphabetic Check • First Name • Adrian • Ad33n NumericCheck • Postal Code • 36109 • 3rto9 • Range Check • Monthly Fee • $39.50 • $95.25 Consistency Check • Date JoinedTraining Date • 10-20-200410-27-2004 • 10-20-200410-13-2004 Completeness Check • Last Name • Valesquez Next • What is validation? • Process of comparing data with a set of rules to find out if data is correct • Reduce data entry errors and enhance data integrity before program writes data on disk p. 10.10 Fig. 10-8

  17. Maintaining Data Check Digitnumber(s) or character(s) appended to or inserted into a primary key value to confirm accuracy of primary key value Alphabetic/Numeric Check ensures correct type of data entered Completeness Checkverifies that a required field contains data Consistency Checktests for logical relationship between two or more fields Range Check determines whether number is within specified range Click to view Web Link, then click Check Digits below Chapter 10 Next • What are the types of validity checks? p. 10.11

  18. File Processing Versus Databases Data redundancy—same fields stored in multiple files Isolated data—data stored in separate files so it is difficult to access Next • What is a file processing system? Each department or area within organization has own set of files Records in one file may not relate to records in any other file May have weaknesses p. 10.11

  19. File Processing Versus Databases Next • What is the database approach? • Many programs and users can share data in database • Secures data so only authorized users can access certain data p. 10.12 Fig. 10-9

  20. File Processing Versus Databases Next • What are the strengths of the database approach? Reduced data redundancy Improved data integrity Shared data Easier access Reduced development time p. 10.13

  21. File Processing Versus Databases Next • How do a database application and a file processing application differ in the way they store data? File Processing Example Database Example p. 10.13 Fig. 10-10

  22. Database Management Systems • Database • Manufacturer • Computer Type Access • Microsoft Corporation • Personal computer, server, PDA DB2 • IBM Corporation • Personal computer, midrange server, mainframe • Informix • IBM Corporation • Personal computer, midrange server, mainframe Ingres • Computer Associates International, Inc. • Personal computer, midrange server, mainframe • Oracle • Oracle Corporation • Personal computer, midrange server, mainframe, PDA SQL Server • Microsoft Corporation • Server Sybase • Sybase Inc. • Personal computer, midrange server, PDA Click to view Web Link, then click Database Management System below Chapter 10 Next • What are popular database management systems (DBMSs)? p. 10.14

  23. Database Management Systems Click to view Web Link, then click Data Dictionary below Chapter 10 Next • What is a data dictionary? • Contains data about each file in database and each field within those files p. 10.14 Fig. 10-12

  24. Database Management Systems Next Step 1. Select the fields you want to display in the resulting query. • What is a query? • Request for specific data from a database • Query language consists of simple, English-like statements that allow users to specify data to display, print, or store Step 2. Assign a name to the query, so you can open it later. Step 3. View query on the screen. p. 10.16 Fig. 10-13

  25. Database Management Systems Next • What is a query by example (QBE)? • Program retrieves records that match criteria entered in form fields • Has a graphical user interface that assists users with retrieving data Query by example screen criteria Query results p. 10.17 Fig. 10-14

  26. Database Management Systems Next • What is a form? • Window on screen that provides areas for entering or changing data in database • Used to retrieve and maintain data in a database • Form that sends data across network or Internet is called e-form, short for electronic form p. 10.17 Fig. 10-15

  27. Database Management Systems Next • What is a report generator? • Allows user to design a report on screen, retrieve data into report design, then display or print reports • Also called report writer p. 10.18 Fig. 10-16

  28. Database Management Systems Next • What is data security? Access privileges define activities that specific user or group of users can perform DBMS provides means to ensure only authorized users can access data Read-only privileges user can view data, but cannot change it Full-update privileges user can view and change data p. 10.18

  29. Database Management Systems Next • What are backup and log? before image • Backup is a copy of the entire database • Log is a listing of activities that change database contents • DBMS places three items in log: before image, actual change, and after image change after image p. 10.19 Fig. 10-17

  30. Database Management Systems Uses logs and/or backups to restore database when it is damaged or destroyed Click to view Web Link, then click Backup and Recovery below Chapter 10 Next • What is a recovery utility? Rollforward—DBMS uses log to re-enter changes made to data-base since last save or backup • Also called forward recovery Rollback—DBMS uses log to undo any changes made to database during a certain period of time • Also called backward recovery p. 10.20

  31. Relational, Object-Oriented, and Multidimensional Databases Next • What is a data model? DATA MODELS FOR POPULAR DBMSs • Rules and standards that define how database organizes data • Defines how users view organization of data • Three popular data models • Relational • Object-oriented • Multidimensional p. 10.20 Fig. 10-18

  32. Relational, Object-Oriented, and Multidimensional Databases Click to view Web Link, then click Relational Databases below Chapter 10 Next • What is a relational database? • Stores data in tables that consist of rows and columns • Each row has primary key • Each column has unique name • Stores data relationships • Uses specialized terminology DATA TERMINOLOGY p. 10.20 Fig. 10-19

  33. Relational, Object-Oriented, and Multidimensional Databases Click to view animation Next • What is a relationship? • Connection within data p. 10.21 Fig. 10-20

  34. Relational, Object-Oriented, and Multidimensional Databases Click to view Web Link, then click SQL below Chapter 10 Next • What is Structured Query Language (SQL)? • Allows you to manage, update, and retrieve data • Has special keywords and rules included in SQL statements SQL statement SQL statement results p. 10.22 Fig. 10-21

  35. Relational, Object-Oriented, and Multidimensional Databases Stores data in objects Advantages Often uses object query language (OQL) Click to view Web Link, then click Object-Oriented Databases below Chapter 10 Next • What is an object-oriented database (OODB)? Object is item that contains data, as well as actions that read or process data • Can store more types of data • Can access data faster p. 10.22

  36. Relational, Object-Oriented, and Multidimensional Databases Multimedia databases Hypertext databases Hypermedia databases Web databases Store images, audio clips, and/or video clips Contain text links to other documents Contain text, graphics, video, and sound Link to e-form on Web page Groupware databases Store documents such as schedules, calendars, manuals, memos, and reports Computer-aided design (CAD) databases Store data about engineering, architectural, and scientific designs Next • What are examples of applications appropriate for an object-oriented database? p. 10.22

  37. Relational, Object-Oriented, and Multidimensional Databases Stores data in dimensions Multiple dimensions, also called hypercube, allow users to analyze any view of data Can consolidate data much faster than relational database Click to view Web Link, then click Multidimensional Databases below Chapter 10 Next • What is a multidimensional database? p. 10.23

  38. Relational, Object-Oriented, and Multidimensional Databases Huge database system that stores and manages data required to analyze historical and current transactions Quick and efficient way to access large amounts of data Often uses a process called data mining to find patterns and relationships among data Data mart is smaller version of data warehouse Uses multidimensional databases Click to view Web Link, then click Data Warehouses below Chapter 10 Next • What is a data warehouse? p. 10.24

  39. Web Databases Click to view video Next • What is a Web database? • Database you access through the Web by filling in a form on a Web page • Usually resides on a database server, a computer that stores and provides access to a database p. 10.24 Fig. 10-23

  40. Web Databases Click to view video Next • How might a search engine interact with a Web database? Step 1. Browser sends search text to Web server. Step 2. Web server sends search text through a CGI script to database. Database retrieves list of hits that contains search text and sends it through CGI script back to Web server. Step 3. Web server sends list of hits to browser. p. 10.25 Fig. 10-24

  41. Database Administration 2. Design the tables 3.Design the fields for each table Next • What are guidelines for developing a database? 1. Determine the purpose of the database • Design tables on paper first • Each table should contain data about one subject • Be sure every field has a unique primary key • Use separate fields for logically distinct items • Do not create fields for information that can be derived from entries in other fields • Allow enough space for each field • Set default values for frequently entered data 4. Determine the relationships among the tables p. 10.26

  42. Database Administration Database administrator (DBA) Database analyst (DA) Click to view Web Link, then click Database Administrators below Chapter 10 Next • What is the role of the database analyst and administrator? • Focuses on meaning and usage of data • Decides proper placement of fields, defines relationships, and identifies users’ access privileges • Creates and maintains data dictionary, manages database security, monitors database performance, and checks backup and recovery procedures p. 10.27

  43. Summary of Database Management How data and information are valuable assets to an organization Advantages of organizing data in a database Methods for maintaining high-quality data Various types of databases Assessing the quality of valuable information Role of the database analysts and administrators Chapter 10 Complete

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